Group size estimator

How many trainers do I need to invite?

The Estimator is already "trainers of this attacker needed to finish inside the timer", so this page does not invent a number: it reads it off the boss's own ranked counter list for three realistic parties and re-simulates each of them at every level from 20 to 50.

Raid bossTierIVsWeatherFriendshipDodgingShadow attackersMega attackersLegendary attackers

Invite 6 to be safe — 5 if everyone is prepared

At level 40, a party of Cloyster's top six counters needs 4.27 trainers (round up: 5), and a mixed lobby of ranks 13-24 needs 5.11 (round up: 6). The raid timer is 300 seconds and one prepared trainer alone would take 19:38. No level in this range makes it soloable with a prepared party.

Cloyster · Elite

waterice

Weak to

fightingrockgrasselectric

Boss CP: 46,794
Boss HP: 20,000
Raid timer: 300s
Party used: 6

Trainers needed, by attacker level

Scroll sideways for the mixed-lobby column.

Trainers needed to beat Cloyster at each attacker level
Attacker level	Six of the best counter	A prepared party	A mixed local group	Prepared solo time	Faints per timer
Level 20	6(5.33)	7(6.64)	8(7.85)	30:32	6.0
Level 25	5(4.44)	6(5.60)	7(6.51)	25:45	6.0
Level 30	5(4.02)	5(4.95)	6(5.75)	22:48	6.0
Level 35	4(3.87)	5(4.67)	6(5.40)	21:30	6.0
Level 40	4(3.78)	5(4.27)	6(5.11)	19:38	6.0
Level 45	4(3.44)	5(4.06)	5(4.91)	18:41	6.0
Level 50	4(3.35)	4(3.93)	5(4.76)	18:05	6.0

Whole trainers in bold, the raw estimator in brackets — 2.04 means two trainers is right on the line and three is comfortable.

Six of the best counter

Every trainer brings six copies of the single best counter — the theoretical floor.

4 trainers at level 40

Keldeo3.78

A prepared party

Each trainer brings the boss's top six counters, powered up and correctly TM'd.

5 trainers at level 40

Keldeo3.78
Lucario4.22
Zeraora4.35
Terrakion4.36
Kartana4.41
Regieleki4.48

A mixed local group

Ranks 13-24: reasonable but unoptimised parties, which is what a public lobby usually is.

6 trainers at level 40

Conkeldurr5.02
Necrozma (Dusk Mane)5.04
Eternatus5.01
Blaziken5.18
Hisuian Decidueye5.01
Electivire5.06

The party these numbers assume

1. Keldeo

Low Kick + Secret Sword

2. Lucario

Force Palm + Aura Sphere

3. Zeraora

Spark + Plasma Fists

4. Terrakion

Double Kick + Sacred Sword

5. Kartana

Razor Leaf + Sacred Sword

6. Regieleki

Thunder Shock + Thunder Cage

See the full ranked counter list for Cloyster · check a real lobby (win chance, who brings what) · make a share card of the top six

How this is worked out

The boss is ranked once at level 40 with rankCached (the same memoised call /raids makes), then the three bands — rank 1, ranks 1-6, ranks 13-24 — are re-simulated at each attacker level with an 8-run Monte Carlo each. Holding the party fixed and moving only its level is deliberate: it answers "what if my party were level 20" rather than "what would a level-20 player's completely different party be", and it is about ten times cheaper than re-ranking every attacker seven times. The Estimator itself is Pokebattler's definition, time to win including rejoin time divided by the raid timer.